Simultaneous Radar Detection and DOA Estimation in the Presence of Unknown Mutual Coupling

Abstract

This paper focuses on the joint adaptive radar detection and target Direction-of-Arrival (DOA) estimation in the presence of mutual coupling among the array elements. A suitable model of the signal received by the multichannel radar is developed via a linearization procedure of the actual Uniform Linear Array (ULA) manifold around the nominal array looking direction. The detection problem is tackled by means of the Generalized Likelihood Ratio Test (GLRT), leveraging a specific Minorization-Maximization (MM) framework, with proven convergence properties, to optimize the concentrated likelihood function under the target presence hypothesis. Besides, when the number of active mutual coupling coefficients is unknown, a Multifamily Likelihood Ratio Test (MFLRT) approach is invoked. The performance of the devised architectures is compared with benchmarks as well as with counterparts neglecting the coupling phenomenon, highlighting the capability of the proposed processing strategies to counteract the steering vector mismatches induced by the mutual counling phenomenon,